de-interlaced means progressive ?

[codemaster]

I want to edit an .M2V in a NLE, but when I convert the .M2V to DV QuickTime using MPEG_Streamclip, I check the option called "de-interlace", because when I analyze the source with MeGUI, is says that it is interlaced. When creating a new project in a NLE, what type of video should I choose, 25i or 25p, knowing that the source of the .M2V is a PAL DVD recorded with a dvd camcorder.

[jagabo]

After deinterlacing the video is progressive. Deinterlacing is generally damaging to the video. You should avoid it if possible.

[codemaster]

After deinterlacing the video is progressive. Deinterlacing is generally damaging to the video. You should avoid it if possible.

if I avoid deinterlacing, meaning that if I convert my interlaced source to DV without deinterlacing, I get skinny black bar at the bottom that flashes and distracts attention from the movie. In my tests, I found out that if I deinterlace, I don't get black lines at the bottom, nor at the top. In fact, in the DV codec settings window of Mpeg Streamclip, above the de-interlace check option, it says: "Deselect for progressive movies".

[edDV]

After deinterlacing the video is progressive. Deinterlacing is generally damaging to the video. You should avoid it if possible.

if I avoid deinterlacing, meaning that if I convert my interlaced source to DV without deinterlacing, I get skinny black bar at the bottom that flashes and distracts attention from the movie. In my tests, I found out that if I deinterlace, I don't get black lines at the bottom, nor at the top. In fact, in the DV codec settings window of Mpeg Streamclip, above the de-interlace check option, it says: "Deselect for progressive movies".

Describe your source format. Is it film source, live broadcast (e.g. news or sports) or other? Is it PAL or NTSC frame rate?

DV Quicktime is interlace. You shouldn't be getting "black lines at bottom" whether interlace or progressive.

[PuzZLeR]

Visually interlaced is not the same as encoded interlaced. Same goes for progressive - visually progressive is not the same as encoded progressive.

For example, you can deinterlace a visually and encoded interlaced video, make it visually progressive but it will still be read as "interlaced" in an app like MediaInfo if encoded as interlaced.

[jagabo]

Deinterlacing will throw away half the temporal resolution and as much as half the spacial resolution, depending on what algorithm is used.

[codemaster]

The source is a recording from a camcorder that records straight into DVD PAL format and writes it on miniDVD discs. I then demux the AC3 and M2V streams using DVD Decrypter, so that I can decode the AC3 stream into WAV using azid_P4 and then convert M2V to QuickTime with MPEG Streamclip using a DV codec. And finally, import the .mov and .wav into NLE for editing.

Here's what MeGUI says about the M2V after analysis:


and here are the settings for converting to dv:

if I don't check "Deinterlace Video" option, the video has a ~2px black bar at the bottom, or at the top in case I change "Field dominance" to "Upper Field First"

when I import the .mov file in NLE, it asks about it's field dominance, I check "bottom field", and after it imports it, it shows a small black bar at the bottom of all frames

[zoobie]

it sounds overly complicated and is probably degrading the PQ (picture quality)

[codemaster]

it sounds overly complicated and is probably degrading the PQ (picture quality)

you mean the picture quality is being degraded by the de-interlacing process? I've tried converting it to DV without de-interlacing and with field dominance set to "upper field first" (the same as the source). And in my NLE, I've set the project format to 25i. Problem is, in NLE and after encoding the edit, the video has a ~2px black line at the top of all frames, wich has an annoying flicker from the beginning till the end of the video.

or do you mean it's complicated and pq degrading to edit a camcorder dvd in NLEs ? do you know a better workflow for editing this kind of camera output format, but still involving transitions, titles, color correction and audio adjustments ? Because I set the quality of DV codec at 100%, wich means no compression, frames do not have data removed from them, only I don't understand the issue with that black line at the top.

[jagabo]

you mean the picture quality is being degraded by the de-interlacing process?

Yes. As I mentioned earlier you are throwing away half the temporal resolution (50 images per second to 25 images per second), throwing away some of the spacial resolution (At least Yadif is one of the better deinterlacers in that respect), and creating artifacts which will forever be in your final video (look for buzzing at sharp, near horizontal, edges).

I've tried converting it to DV without de-interlacing and with field dominance set to "upper field first" (the same as the source). And in my NLE, I've set the project format to 25i. Problem is, in NLE and after encoding the edit, the video has a ~2px black line at the top of all frames, wich has an annoying flicker from the beginning till the end of the video.

Only when previewing in the NLE? Or is it also in the output file? It might only be a problem with the program's real-time deinterlacing for preview. There should be no problem going from interlaced DVD to interlaced DV. You'll probably need to reverse the field order of the video (interlaced MPG is usually TFF, interlaced DV is always BFF). Encoding with the wrong field order will result in fast-jerky playback.

[poisondeathray]

Because I set the quality of DV codec at 100%, wich means no compression, frames do not have data removed from them, only I don't understand the issue with that black line at the top.

But DV is lossy, so there is quality loss when you convert to DV

What editor are you using? Many can accept MPEG2 natively

And what is your end format goal? Make a DVD? Web video ? PC playback ?

Can you post a sample or screenshot of the black line? It only disappears when you deinterlace? This doesn' t make sense

[poisondeathray]

I played with mpegstreamclip and a PAL mpeg2 clip. It's causing the 2px shift on the top. It also screws up the levels (contrast is expanded)

[codemaster]

here is a sample test.mp4
just a test video to show that at the bottom of each frame there are some black dots flickering, but those are not present in the source M2V

the M2V was converted to DV without de-interlacing

[edDV]

here is a sample
[Attachment 4790 - Click to enlarge]
just a test video; at the bottom of each frame there are some black dots flickering, but those are not present in the source M2V

the M2V was converted to DV without de-interlacing

Why DV format? Is this a Mac?

Most editors will edit MPeg2 directly. Many will take AC3 too.

[codemaster]

Only when previewing in the NLE? Or is it also in the output file? It might only be a problem with the program's real-time deinterlacing for preview. There should be no problem going from interlaced DVD to interlaced DV. You'll probably need to reverse the field order of the video (interlaced MPG is usually TFF, interlaced DV is always BFF). Encoding with the wrong field order will result in fast-jerky playback.

except there is this problem when I convert interlaced m2v to interlaced dv, as demonstrated in the sample above, wich represents a m2v (with upper field first) converted to dv (with lower field first), imported in a NLE and exported as mp4

if I encode to dv with upper field order, the exported mp4 has to many artifacts flickering at the top of every frame; at least with dv lower field order, those artifacts that appear at the bottom are much smaller in height

i'm not sure if the field order of the m2v and dv must be the same, but even if they are, those artifacts are still present

[jagabo]

except there is this problem when I convert interlaced m2v to interlaced dv

That's why I emphasized there should be no problem. The software you are using isn't working well.

There are two basic ways to swap field order: shift the frame up or down by one scan line; or separate fields, throw out the first field, then recombine fields. The first method leaves a question of what to do with the empty scanline at the top (frame shifted down) or bottom (frame shifted up). Typcially it's left blank (black) or just copied from the adjacent line of the same field. And with YV12 video there is also the issue of additional blurring of the chroma channels. The second method causes a temporal shift, the duration of one field.

[codemaster]

Typcially it's left blank (black) or just copied from the adjacent line of the same field.

it makes more sense now, because NLE displays a black line at the bottom of all frames (if the field dominance of the imported dv is lower field first), and only the encoder, Sorenson Squeeze, outputs a file in wich all the frames have weird artifacts flickering only in that 1px or 2px line at the bottom (probably because of the auto-deinterlace filter, but I'm not sure). I think one solution would be to crop the video in Sorenson by the number of pixels occupied by that black line.

[lordsmurf]

The problem here lies in the workflow and software choices.
Start over.

I want to edit an .M2V in a NLE

Convert it to another intermediary first. Problem solved. HuffYUV is my suggestion.

[codemaster]

The problem here lies in the workflow and software choices.
Start over.

Convert it to another intermediary first. Problem solved. HuffYUV is my suggestion.

That workflow is for fast importing in Media Composer without transcoding, only wrapping in MXF, and it is one of the workflows suggested on avid community forums. All other workflows suggested there, involve converting mpeg to quicktime using avid dv codec, but using different expensive apps. MPEG Streamclip is free, and from what "jagabo" says, it seems that the black line at the bottom is something normal.

[lordsmurf]

M2V is not DV.
DV is native bottom-field interlace, MPEG-2 is top.
So your problem probably comes from that discrepancy, and choice of software.

You seem to be converting M2V to DV from what I see above.
DV is compressed anyway, HuffYUV is lossless. My method is better.